Spain's Rafael Nadal signs autographs after defeating Germany's Daniel Brands in their first round match of the French Open tennis tournament, at Roland Garros stadium in Paris, Monday, May 27, 2013. Nadal won in four sets 4-6, 7-6, 6-4, 6-3. (AP Photo/Michel Euler)
/ AP

PARIS 
Rafael Nadal favors more transparency in tennis drug testing even though he says the sport is clean.

Speaking after a first-round victory Monday at the French Open, Nadal bristled when asked about the frequency of testing. He favors revealing who is being tested and how often. He says if such procedures were in place, such questions about drug testing would not have to be asked.

All top players are subject to testing without warning. Nadal says the results reflect well on the tour.

Nadal, a former member of the ATP Player Council, says tennis is a "very clean sport." He adds: "We don't have a lot of cases of doping."